不同改良剂对土壤-叶菜系统Cd迁移累积的调控作用

为筛选适合在中轻度镉污染土壤上有效降低叶菜吸收镉的改良剂及用量,采用镉污染菜地土壤进行盆栽试验,研究不同用量的石灰、泥炭和碱渣对小白菜（Brassica chinensis L.）生物量、镉吸收量,土壤pH及有效态镉含量的影响。结果表明,3种改良剂对小白菜生长均无显著的抑制作用;与不施改良剂的处理相比,石灰、泥炭显著抑制小白菜对镉的吸收,地上部镉含量与石灰和泥炭用量均呈显著负相关关系（R=-0.668、-0.785,P〈0.05）,碱渣对小白菜地上部镉含量的影响不显著,但显著增加根系镉含量;改良剂均显著提高土壤pH,但对DTPA-Cd影响不同,石灰显著降低DTPA-Cd,泥炭、碱渣均有增加DTPA-Cd含量的趋势;泥炭对土壤-小白菜系统Cd迁移的调控效果最佳,其最佳用量为20 g.kg-1土,石灰次之,碱渣不适合。

Effect of Different Amendments on Translocation and Accumulation of Cadmium in the Soil-Brassica Chinesis System

Cadmium（Cd）is one of the most toxic and serious environment polluting heavy metals.The application of amendments is an im-portant approach to remediate Cd contaminated soils.A pot experiment was conducted to study the effects of three amendments（lime,peat,alkali slag）and their application dosage on biomass and Cd uptake of Brassica chinesis,soil pH,and DTPA-extracted Cd in a Cd contami-nated horticultural soil,and to select the suitable amendments for remediating large areas of Cd contaminated farmland soil.The obtained re-sults indicated that applications of three amendments did not inhibit the growth of Brassica chinesis.Lime and peat inhibited Cd uptake of Brassica Chinesis compared with the control treatment,and there was a positive correlation（R=-0.668,-0.785,P0.05）between the in-hibitory effect and the application dosage.However,alkali slag showed no obvious effects on shoot Cd concentration,but significantly in-creased root Cd concentration of Brassia chinensis.Three amendments all improved soil pH,but they had different effects on the DTPA-extracted Cd.Lime greatly decreased DTPA-extracted Cd but alkali slag and peat had both tended to increase DTPA-extracted Cd.Among three amendments,the peat was showed to be the best one for decreasing the shoot Cd,and the optimum was 20 g.kg-1.Second one was lime.Alkali slag was not suitable to be used as an amendment to remediate Cd contaminated soil.